A New Gravimetric Geoid Model for the Area of Sudan Using the Least Squares Collocation and a GOCE-Based GGM

The determination of an accurate geoid model remains an important challenge for geodetic research in Sudan. The presented contribution concerns the determination of a new gravimetric geoid model (SUD-GM2014) for the area of Sudan using recent released GOCE-based Global Geopotential Models (GGMs), available terrestrial mean free-air gravity anomalies and the high-resolution SRTM30_PLUS global digital elevation model. The computations of the SUD-GM2014 were performed using remove-compute-restore (RCR) procedure and the least squares collocation method. The residual terrain modelling (RTM) reduction method was applied to estimate the topography effect on the geoid. The resulting gravimetric geoid model has been evaluated using geoid heights at 19 GNSS/levelling points distributed over the country. The evaluation results and the expected quality of the SUD-GM2014 geoid model were discussed considering the quality of GNSS/levelling data in Sudan. The SUD-GM2014 or the geoid model computed from GOCE-based GGMs only has been recommended as reference for GNSS heighting in Sudan.